I paired a cheap $125 PSU with a $3,000 RTX 5090

When you’re building a new gaming PC or upgrading an existing build, you want to make sure that every dollar is spent optimally and that you’re not spending more than you have to.

The power supply unit is the last place you want to cut if you need to save cash. A low-quality PSU can take out some or all of the components connected to it should it fail, and less efficient units throw off more heat and suck down more power from the wall than a high-end 80 Plus Gold or Platinum unit might.

Even with that advice in mind, the temptation to save always beckons. I recently needed to get a new PSU for one of my PCs, which is built around a notoriously power-hungry Core i9-13900K. That system only sees occasional use and wouldn’t benefit much from an expensive, exotic PSU, so I didn’t want to spend a cent more than I had to in order to keep it running.

Since that PC will occasionally see use with a 575W GeForce RTX 5090, though, I figured I’d need a pricey 1200W unit from a marquee OEM to ensure enough headroom in scenarios where both CPU and GPU might be under heavy multitasking loads. Those PSUs sell for about $175 to $250 or more on Amazon and Newegg.

To guide what I thought was going to be a spendy decision, I turned to our own best PSUs list, where I discovered Montech’s Century II. We reviewed the 1050W unit in this line and found it worthy of our Editor’s Choice award thanks to its clean power, high efficiency, 10-year warranty, and quality components.

Montech also makes a 1200W model in this family, and I was shocked by its price tag: just $125 on Newegg, or anywhere from $50 to $150 less than high-end 1200W units from other brands.

In an era where everything seems to be getting more expensive by the day, I was worried that such a tantalizingly low price tag surely came with a catch. But with our stamp of expert approval, I figured I had nothing to lose by giving it a shot, so I put in my Newegg order.

Having worked in and around PCs long enough to see plenty of cost-cutting measures, I opened up the Century II’s box expecting at least some concessions to its low price, but nothing immediately stood out. If anything, this unit’s flat, capacitor-free cables are an upgrade over the bulky modular cords common on PSUs I’ve used in the past few years.

Even the critical 12V-2x6 cable comes built to the 5090-worthy baseline you’d want: a 600W rating printed on the connector, along with 16-gauge wiring and an 80 °C temperature rating.

This GPU power cable does have a separate bundle of sense wires flopping around, unlike some nicer custom cables available from aftermarket sources like MODDIY that hide those wires alongside the main current carriers. Those aftermarket cables are 25% of the price of this power supply alone, though. I think I can add a couple strategically-placed cable ties and live.

Before committing this PSU to its final home, I put it through its paces on our GPU test bench with an RTX 5090 from our fleet. After more than an hour of load with Unigine’s torturous Superposition benchmark, and with active airflow from a low-speed 140mm case fan nearby, the provided 12V-2x6 cable was certainly warm at the GPU end, but at about 125 °F or 52 °C measured just shy of the connector proper, it was well within its 80 °C rating.

I also checked the exhaust temperature of the PSU to see whether it was operating under any particular strain and found that it was gently blowing 95 °F (34 °C) air from its rear panel. No problems here.

The Century II’s fan does audibly spin up even in the 50%-60% load range, but its sound isn’t objectionable and will certainly blend into the overall sound signature of a powerful PC under load. I also appreciate that its semi-silent hybrid mode can be disabled in the event that your case only has a bottom PSU intake. PSUs without defeatable semi-silent modes can allow hot air to build up in their upside-down chassis, potentially shortening their life spans.

With my initial bench testing out of the way, I moved the Century II into my Core i9-13900K-powered rig, along with the same RTX 5090 from earlier. To see how this unit handled the worst I’d ever throw at it, I fired up Cinebench’s multithreaded stress test on loop on the i9-13900K, alongside the Superposition benchmark on the 5090 once again.

Under those workloads, my trusty Watts Up meter read a whopping 1044 W coming from the wall, or 87% of this Century II’s rating. The unit’s exhaust temperatures rose to 125 °F under that load, and inside the case, the 12V-2x6 cable’s temperature got all the way up to 132 °F (54 °C) at its hottest point—still well within its 80 °C peak rating.

It’s worth noting that many games don’t push an RTX 5090 to the extreme power-draw limits that Superposition does, so if this cable can handle that load for extended periods, I fully expect it’ll be fine in more typical use.

So there you have it. If you’re putting an RTX 5090 and a many-core CPU on your parts list, you might figure (like I did) that you’ll want a hulking 1200W or 1500W PSU that might run you $175 or much, much more.

But if, for some reason, you have to free up dozens or hundreds of dollars for another component in your high-powered build, or you just want to save some money overall, it’s easy to see why Montech’s Century II earned our Editor’s Choice nod. It does everything you need and nothing you don’t right out of the box, all at an incredible price.

The 12V-2x6 cable is the single most likely point of failure for any modern PSU, and even under the stress of an RTX 5090 running all-out in a case, Montech’s included cable didn’t reach troubling temperatures or exhibit hot spots under our thermal camera that might indicate an unbalanced load across its wires.

This PSU is the kind of value that makes you feel like you’re getting away with something, and in an era where that kind of roguish spirit is increasingly absent from PC building, it’s nice that Montech lets us feel like we’re in on a secret.